<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <script>
      //默认是非严格模式
      'use strict'
      var a = 100
      // delete a
      var a = 'asdfas'
      console.log(a)
    </script>

    <script>
      //这里仍然是非严格模式
    </script>
  </body>
</html>
